Gas compressor



Jan.- 23; 1923. S 1,443,135.

` J. G. LAFFERTY.

GAS COMPRESSOR.

man Nov. 1s. |920.

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lpnltnttlted il n NAMENS G. LAEIIFERTY, @1F CURAUPOLJISfPENNSYLWANJIA.

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Application tiled November 16, 19520. 'Serial No. lttll.

.To all whom it may concern:

Be it known that lh'JAivrns Gr. LAFFERTY, a citizen of the United States, and resident of vCoraopolis, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Gas Compressors; and l do hereby declare the following to` be a full, clear, and exact description thereof.

ll/ly invention relates to apparatus for compressing gases, and more especially for compressing oxygen.

'The object of my invention is to provide an apparatus for compressing oxygen and other gases which shall be simple in construction and safe in operation.

More particularly the/object of my invention is to provide an apparatus for compressing oxygenand other gases having improved means for lubricating the compressing cylinders and their piston rods.

Another object of my invention is to provide a compressor for oxygen andy other gases having an improved valve for introducing the gas into the compressing cylinder Aand removing it therefrom, and also to provide a compressor with an improved arrangement ofc linder pistons and with improved means or cooling the cylinders.

The process of compresslng oxygen and other gasescontaininglarge proportions of oxygen has heretofore been a matten of considerable difficult because, when the oxygen is compresse and heated in the compresser, it vis in a condition favoring chemical action and when the workingfparts of the compressor are lubricated by means of ordinary lubricating oils the highly conipressed and heated oxygen attacks the lubricating oil with great violence which results in burning out the lubricatlng packings and often produces dangerous explosions. Also, a great amount of heat is lib-f` erated in the compression of a` heavy gas such as oxygen and ordinary air compressors arel not equipped with sufficient means for disposing of this excess heat.

'lin order to avoid the difficulties encountered when oil is used as a lubricant, attempts have been made tolubricate oxy en compressors with soap solutionA or -with g ycerine. 'lhese lubricants are satisfactory to a limited extent only, because the soap solution tends to take upI oxygen, which maycause water has heretofore been used as a lubricant, being introduced with the gas to be compressed, but in the attempts which have heretofore been made to use water in this way, the cylinders have not been properly lubricated because the pistons have been provided with ordinary metal packing rings which permit the water to evaporate quickly through the heat developed in the cylinder and pass off through the discharge valve. According to one feature of my present invention, l improve the compressor cylinders in this respect by providing each of .them with a packing ring of water-absorbing material which retains the water introduced with the gas and distributes it evenly over the walls of the cylinder.

Another feature of my invention consists in providing a water seal around the piston rods of the cylinder, which prevents'oil from working up the piston rods from the crank shaft, wrist, pins and guides, and thus operates as an additional safety device. y

The third main feature of novelty in my present compressor consists in an improved valve by means of which the as to bey compressed -is introduced into eac cylinder and removed therefrom through a single port, an arrangement which greatly simplifies the construction of the c linders and pistons, and makes them readily accessible without disturbing the valve. Also. the suction and discharge valves are placed side by side, so that each is separately accessible without removing or changing the other.

For a more detailed description of my compressor, reference may now be had .to the accompanying drawing, in which Fig. l is a longitudinal sectional view through a comressor constructed in accordance withv my invention; Fi 2 is a plan view of the structure of ig. 1; and Fig. 3 is a vertical central sectional view through a moditied form of cylinder.V

Referring to Figs. 1 and 2 of the drawing, the compressor therein' shown is a threevstage compressor and comprises a large cylinder 2, an intermiate cylinder t, d

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a small cylinder 4 enclosed within a tank 5 which is provided with a water inlet 6 and a water outlet 7, the inlet 6 being controlled by a valve 8. The tank 5 has a false bottom 9 surrounding the lower' ends of the cylinders 2, 3 and 4 which extend through openings in the false bottom 9 and are supported on annular flanges 10, gaskets 11 being provided to make the joints watertight. Between the false bottom 9 and the bottom 12 of the tank 5 is a space that is kept partly filled with water 13 which is introduced through an inlet pipe 14 and is drawn ofi through an outlet pipe 15, the outlet pipe l5 being connected to the outlet pipe 7.

Each of the cylinders is provided with al,

piston 16 having a plurality of ordinary metal packing rings 17. As shown in Fig. 1 the piston 16 hasV a central hub 18 surrounded by a ring 19 that is attached to the main portion of the piston 16 by means of screws 20. A lubricating ring 21 of fiber felt or other water-absorbing material is clamped between the ring19 and the main portion of the piston 16 and forms a packing ring. In order to provide more ready access of moisture tothe absorbent ring 21, a series of openings 22 is provided in the ring 19.

The pistons 16 are provided with pistony rods 23 which extend through stuffing boxes 24 in the bottom plate 12 of the tank 5 and are connected at their lower ends to cranks 25 carried b the usual crank shaft 26 which is driven rom any suitable source of power, not shown.

In the form of my compressor shown in Figs. 1 and 2, each cylinder is provided with a special form of valve 27, which is shown in detail in connection with the cylinder 2 and consists of a block 28 which is tapped to receive an inlet connection 29 and anoutlet connection 3,0. A passage 31 leads from the inlet connection 29 to an inlet check valve 32 and a. passage 33 connects the inlet valve 32 to a horizontal passage 34 ycommunicating with the interior of the cylinder. The passage 34 is a common inlet and outlet passage and the gas, as it leaves l the cylinder,- passes through the passage 34 and through a. .passage 35, an outlet check valve 36 and a passage 37, to the outlet connection 30. Each of the inlet valves 32 may be provided with' a water connection 38 through which water is introduced into the cylinders for lubrication.

Gas enters the compressor through a pipe 40, passes through the first rvalve and the cylinder 2 in the manner just described, and leaves the first cylinder through a pipe 41 which is connected to a coil 42 surrounding all three of the cylinders and serving to cool the gas, which has been heated by compression in the cylinder 2. The lower end of the coil 42, as shown at the right of Fig. 1,-is connected by means of a vertical pipe 43 to the upper end of a coil 44 which surrounds the cylinder 2, and the lower end of the coil 44 is connected by means of a pipe 45 to'an inlet connection of' the valve 27 of the second cylinder 3. On leaving the second cylinder 3 the gas passes through a coil -46 surrounding the cylinder 3 and from the lower end of the coil 46 it passes through a pipe 47 into the valve of the cylinder' 4. On leaving the cylinder 4 the gas passes through a coil 48 surrounding the cylinder 4 and from the lower end of the coil 43 the gas is led through a pipe 49 out of' the compressor and to a suitable container.

In the modified form of cylinder construction shown in F ig. 3, the cylinder is provided with an inlet valve 5() at the bottom of the cylinder and with two discharge valves 51 at the top of the cylinder. The piston 16 carries a check valve 52 to which communication is provided from beneath the cylinder through passages The gas enters the cylinder through an inlet pipe 54 and the valve 50, and on the down-stroke of the piston the gas passes freely through the piston, through the passage 53, and the check valve 52. On the up-stroke of the piston the check valve 52 pre-vents the gases from returning through the )iston and the gases are compressed and forced out through the discharge valves 51.

The valve construction 'shown in Figs. 1 and 2 has the advantage thatl both the inlet and outlet valves are contained in one valve casing, so that the cylinder head may be removed for inspection or repair of the piston without disturbing the valves or their pipe connections.

1n the operation of my compressor, the oxygen or other gas to be compressed is introduced through the pipe 40, and a suitable quantity of water' for lubrication is introduced through the pipe 38. The gas passes successively through the several cylinders and coils in the manner described above, entering and leaving each cylinder through the common inlet and discharge passage 3K4. Additional water for lubrication is admitted to the second and third cylinders through the pipes 38. The water which is carried into the compressor by the gas is retained by the absorbent packing rings 21 and the walls of the cylinder are therefore evenly and thoroughly lubricated. The piston rods 23 are also lubricated by means of the water seal 13 which surrounds the stufiing boxes 24 and this water seal also serves to prevent oil from creeping up from the crank shaft, wrist pins and guides, and reaching the cylinders. It' any oil should work up through the stuffing box, it will spread in a thin film over the water 13, and will pass off with the water through the outlet pipe 15. On account of the effective water lubrication and the water seal around the piston rods,

tarea a pipe 55.

llt will be evident that ythe apparatus which l have shown and described may be modified in' various respects Without departing from my invention and ll therefore` desire/that no limitations be imposed upon my invention except such as are indicated in the appended claims.

-][ claim as my invention: v

'1. A gas compressor comprising a tank having a false bottom spaced above its true bottom, a cylinder disposed in the said tank above the said false bottom, a piston working in the said cylinder, a piston rod` connected to the said piston` and extending through a stuHing box carried by the true .bottom of the said tank, and means :for causing water to flow around and overthe said 'stuffing box.

2. A gas compressor comprising a tank disposed in said tank ing in said cylinder'and provided with a lubricating member of water-absorbent material, a piston rod connected to said piston and extending through a stuffing box carried by the true bottom ot said tank, and means for causing water to dow around and over the said stung box.

3. Agas compressor comprising a tank having a falsebottom spaced above its true bottom, a cylinder disposed in said tank above the 'said Vfalse bottom, a piston working in said cylinder, va lubricating member 'of water absorbent material carrie by said piston, lsaid piston being .provied 'with openingsA for admitting moisture to said lubricating member, a piston 4rod connected to said piston, and means for providing a water seal around said piston rod.

4. A gas compressor comprising a tank having a false bottom spaced above its true bottom, a cylinder disposed in said tank above said false bottom, a piston working in said cylinder and comprising a body portion having a central hub and an annular member surrounding the said hub, and having a plurality of perforations, an annular member of water-absorbent material dis- Iposed between said body portion and said perforated annular member, and means for securing the said members together.

5; A gas compressor 4comprlsing a tank having a. false bottom spaced above its true bottom, a cylinder disposed inl said tank above said false bottom, a piston working in said cylinder, said piston comprising a hub, an annular member surrounding-said hub and lcarrying a packing ring, an annular lubricating member of water-absorbent material disposed between said hub and said annular member, and means for securing said members together.

y6. A gas compressor comprising a `tank having a false bottom and provided with mea-ns for causing water to flow through both the upper and lower portions thereof, a plurality of cylinders'supported upon the sald Vfalse bottom, pistons working in the said cylinders, piston rods connected to the said pistons I'and extending downward through thetrue bottom `of the tank, stuiing boxes surrounding the said rods and adapted to be covered with water, pipe coils surrounding the said cylinders, and means for introducing gas successively through the said cylinders andthe said coils.l

In testimon whereof, l the said JAMES G. LAFrER'rY, ave hereunto set my hand.

JAMES G. LAFFERTY. Witnesses:

R. D. BROWN, JOHN l". Inn. 

